Termination for electric cable and fluid filled cable conduit

ABSTRACT

An electric cable emerging from a liquid-filled chamber under pressure, such as a deep well casing, is led through a high pressure hose or other conduit to a self sealing terminator in which the conduit and cable sheathing is terminated and from which the cable conductors alone emerge. The terminator comprises a tubular shell having a sealed tubular piston therein and a closure cap at its outlet end. The pressure hose is connected to the incoming end of the terminator shell and the cable is led into and through the piston. All cable sheathing and armor is terminated at the piston and the cable conductors continue through the closure cap. A body of resilient sealing material between the piston and closure cap is compressed by fluid pressure on the piston to seal against the cable conductors.

United States Patent Schneider et al.

TERMINATION FOR ELECTRIC CABLE AND FLUID FILLED CABLE CONDUIT Inventors:Harold N. Schneider, Springfield; J. Kenneth Wittle, Berwyn, both of IPa.

Assignee: General Electric Company, Philadelphia,Pa. Filed: May 5, 1972Appl. No.: 250,658

US. Cl 174/23 R, 166/65 R, 174/20,

Int. Cl H02g 15/04 Field of Search 174/18, 19, 20, 23 R,

References Cited UNITED STATES PATENTS 2/1951 Pouzet 174/20 4/1959Stecher 5/1962 Diehl 174/19 Primary ExaminerLaramie E. Askin Attorney-J.Wesley Haubner. Frank L. Neuhauser. Oscar B. Waddell et al.

[57] ABSTRACT An electric cable emerging from a liquid-filled chamberunder pressure, such as a deep well casing, is led through a highpressure hose or other conduit to a self sealing terminator in which theconduit and cable sheathing is terminated and from which the cableconductors alone emerge. The terminator comprises a tubular shell havinga sealed tubular piston therein and a closure cap at its outlet end. Thepressure hose is connected to the incoming end of the terminator shelland the cable is led into and through the piston. All cable sheathingand armor is terminated at the piston and the cable conductors continuethrough the closure cap A body of resilient sealing material between thepiston and closure cap is compressed by fluid pressure on the piston toseal against the cable conductors.

8 Claims, 2 Drawing Figures PATENTED M 1 2 I975 sum 1 are PATENTEB I r:V. I

TERMINATION FOR ELECTRIC CABLE AND FLUID FILLED CABLE CONDUIT Ourinvention relates to terminal apparatus for an electric cable and afluid filled enclosing conduit, and

particularly to termination of a long electric cable emerging from awater and/or oil filled chamber under high fluid pressure. The inventionis specially applicable to above ground termination of an electric cabletraversing a long fluid filled chamber or casing to transmit substantialamounts of electric energy to an underground location, as for certainoil well processes or equipment.

It is a general object of our invention to provide means for terminatingan electric cable at a location remote in respect to or at its point ofemergence from a high pressure fluid filled chamber.

It is another object of our invention to provide improved means forabove ground termination of a long armored electric cable connectedthrough a liquid filled well casing to equipment at an undergroundlocation.

It is a more particular object of our invention to provide an extendedor remote self-sealing terminator for an electric cable and enclosingconduit emerging from a main liquid-filled chamber under pressure.

In carrying out our invention in one preferred embodiment we positionhigh voltage electric apparatus in a deep bore hole having a casingthrough which an armored electric cable passes from above the earthssurface to the down-hole apparatus. The casing is sealed at its headwith a pressure cap and is filled with conductive water or otherelectrolyte under high pressure to cool the electrode and to provide acurrent path between the electrode and the earth. Pressures contemplatedin such a casing are of the order of 2,500 to 3,300 pounds per squareinch. In such an application it is not desirable to terminate the cabledirectly at the casing cap, for if any fault, as due to high fluidpressure, develops at this point it is necessary to withdraw and replacethe entire length of cable.

To terminate such en electric cable above ground level we bring itthrough the casing cap into an extended conduit, which may be flexibleand is preferably at least several feet in length, and provide a remotetermination for the cable and the extended conduit. The remotetermination structure comprises a tubular shell having a tubular pistonslidably mounted therein with a sealing ring therebetween. The electriccable is brought into the tubular piston where the cable armor and outercable insulation is terminated. The terminated end of the cable armor isconnected to the piston and beyond the cable armor resilient sealingmeans is clamped between the outer cable insulation and the tubularpiston. Fluid under pressure in the extended conduit and the terminatorshell bears against the incoming end of the sealed piston and presses aninternally flared conical surface at the other end of the piston againsta body of resilient sealing material which is backed up by a fixed stopin the terminator shell.

Our invention will be more fully understood and its several objects andadvantages further appreciated by referring now to the followingdetailed specification taken in conjunction with the accompanyingdrawing in which:

FIG. 1 is an axial cross sectional view of a capped well casing andextended electric cable conduit having at itsend a coupling flange forconnection to the incomingend of a self sealing conduit and cableterminator shown at FIG. 2, and

FIG. 2 is an axial cross sectional view of a self sealing conduit andcable termination structure constructed in accordance with our inventionfor connection to the extended conduit shown at FIG. 1.

Referring now to the drawing we have shown at FIG. 1 a well casing 1providing a chamber at least several inches in diameter and extendinginto the earth for a distance of several hundred or several thousandfeet to provide a fluid filled chamber. An armored and insulatedelectric cable 2 is positioned within the well casing 1 and emerges fromit above ground level. Above ground the well casing l is capped at awell head comprising a flanged sealing collar 3 and a closure plate 4.Internally the well head collar 3 includes a positioning plate or disk3a in parallel spaced relation with the closure plate 4 and againstwhich a plurality of packing glands 5 and a pressure plate 6 arestacked. Aligned apertures in the closure plate 4, the positioning disk3a and the intermediate sealing disks provide for entry of a watersupply pipe 7 and a cylindrical cable ferrule 8 through the well head insealing relation. In assembly a pressure annulus or ring 9 interposedbetween the pressure plate 6 and closure plate 4 and telescopedinternally within the collar 3 applies pressure through the plate 6 tothe packing glands 5 when the closure plate 4 is bolted in place. Wateris supplied through the pipe 7 preferably under substantial pressure andfills the well casing l.

Externally of the well head the cable ferrule 8 is provided with athreaded coupling 8a to which is connected a tubular extended cableconduit, shown as a flexible hose 10 having at its other end a flangedcoupling 11. The electric cable 2 passes loosely through the ferrule 8and the extended conduit 10 so that water under pressure fills theferrule and the extended conduit up to and beyond the conduit coupling11, as will be evident by referring now to FIG. 2.

At FIG. 2 we have shown in axial cross section a remote cable andconduit terminator bolted to the hose coupling flange 11. The terminatorcomprises a cylindrical metallic shell 20 having a mounting flange 20aat its lower or incoming end bolted to the hose coupling 11 and providedat its opposite outgoing end with a threaded end cap 21 centrallyapertured to permit egress of the insulated cable conductors. In theillustrated embodiment of the invention we have shown a plural conductorcable comprising three conductors 22, 23 and 24 each separately enclosedin a suitable insulating jacket of rubber or the like, a commoninsulating tube or jacket 25 enclosing all the conductors and formed,for example of nitril rubber or the like and a tubular external metallicarmor sheath 26 which is preferably flexible and formed of woven orspirally wrapped metallic strands in a manner well known to thoseskilled in the art.

The entire armored cable is brought into the terminator shell throughthe incoming end of the shell; the cable armor 26 and common insulatingjacket 25 are terminated within the shell 20 and the insulatedconductors 22, 23 and 24 pass out through the end cap 21 at the outgoingend of the shell.

Within the terminator shell 20 and adjacent its incoming end we providea tubular slidable piston having a lower end or base 30 mechanicallyconnected to the terminated end of the cable armor 26 and an upper orhead portion 31 peripherially sealed to the terminated end of theinsulating cable jacket 25. The two part piston 30-31 is preferablyformed of metal with thetwo parts bolted together and is slidablymounted within the terminator shell 20 to enable water under pressureadmitted to the lower part of the shell to move the piston intocompressive relation with a body of resilient sealing material 35interposed between the upper end of the piston and the closed outgoingend of the terminator shell. To prevent passage of liquid below thepiston through the annular space between the piston and shell suitablesealing means, such as an O ring-36, is provided between the shell andthe piston head.

The piston base 30 includes a tubular lower portion of reduced diameterto which the terminated cable armor 26 is mechanically connected, as bysoldering of a ring 37 to the piston base and to the armor sheath.

The piston head 31 is formed internally with outwardly flared upper andlower conical surfaces forming oppositely directed mouths with a narrowthroat there- 'between. The terminal end of the insulating cable jacket25 passes through the throat of the piston and the flared mouth of thepiston head 31. Within the lower or incoming conical mouth of the pistonhead there is positioned a tubular resilient gasket 40 which bearsinternally against the insulating cable jacket 25 and is compressed intothe lower conical mouth of the piston head 31 by engagement at its lowerend with an upper internal conical surface 41 of the piston base 30. Itwill be evident that when the piston base 30 and piston head 31 aredrawn together by connecting bolts 42 the intermediate gasket 40 iscompressed axially into the conical lower mouth of the piston head andthus pressed radially against the outer surface of the cable jacket 25.This sealing effect is further enhanced by exposing a portion of thelower end of the gasket 40 to fluid under pressure admitted between thecable jacket 25 and the piston base 30 as at an annular surface 43.

The flared upper conical mouth of the piston head 31 bears against thelower end of the elastomeric sealing material 35 which may, for example,be formed of butyl rubber or the like. Within this upper conical mouththe cable jacket 25 is terminated. The separately insulated cableconductors 22, 23 and 24 extend through the body 35 of cast resilientgasket material and out of the terminator shell through the upper endcap 21. Within the terminator shell and between the resilient gasket 35and the closure cap 21 we provide a fixed plug of rigid cast insulatingmaterial 45 which may, for example, be formed of epoxy resin or thelike. Plug 45 is apertured axially to receive the three separateelectric conductors 22, 23 and 24 and has an upper conical outer surface1 fitting into an internal conical surface in the end cap 21. At itslower end each of the three cable apertures through the stop plug 45 isprovided with an outwardly flared conical mouth or entrance, as at 450,within which the resilient gasket 35 extends. Preferably the rigidinsulating plug 45 is also provided with a transverse passage 47 and aconnecting axial passage 48 through which excess gasket material 35 maybe forced.

It will now be observed that with the terminator assembled asillustrated at FIG. 2, fluid pressure applied to the bottom of theinternal piston 30-31- and to a lower surface of the piston gasket 40acts-both to press the piston upwardly within the shell 20 and tofurther compress the gasket 40 within the piston. The gasket 40 isthusadditionally sealed against the cable jacket 25 and the piston 30-31is pressed by fluid pressure against the resilient sealing plug 35. Theplug 35 is thus compressed between the flared upper conical mouth of thepiston head 31 and the downwardly flared conical mouths of the rigidinsulating stop plug 45. The gasket body 35 is thus pressed firmlyagainst the cable conductors 22, 23 and 24 along the full length oftheir passage through the gasket 35 and is also sealed tightly againstthe inner wall of the terminator shell 20 where it engages the shellbetween the piston head 31 and the stop plug 45. In this manner fluidunder pressure confined belowthe tubular piston 30-31 acts to increasepressure on all the gasket seals bearing upon the cable jacket 25 andthe insulated conductors 22, 23 and 24 and effects a self sealing actionwhich ensures that the pressurized fluid does not have access to thecable at any point above the terminated end of the cable jacket 25.

While we have shown and described a preferred embodiment of ourinvention by way of illustration, many modifications will occur to thoseskilled in the art and we therefore wish to have it understood that weintend in the appended claims to cover all such modifications as fallwithin the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. Terminal apparatus for a pressurized fluid conduit and an enclosedelectric cable having a fluid impervious insulating jacket whichcomprises, a tubular shell enclosing said cable and having an incomingend coupled to said conduit, an apertured closure cap in the oppositeoutgoing end of said shell, said cable jacket being terminated withinsaid shell and said cable including an insulated conductor passing outofsaid shell through said closure cap, a tubular piston slidably mountedin said shell and embracing the terminal end of said cable jacket insealed relation, and a body of resilient insulating material fillingsaid shell between said piston and said closure cap and surrounding saidinsulated conductor whereby fluid pressure on the incoming side of saidpiston increases sealing pressure of said resilient body against saidinsulated conductor.

2. Terminal apparatus according to claim 1 which includes also a sealingring interposed between said piston and said shell.

3. Terminal apparatus according to claim 1 for an electric cable havingan external metallic armor sheath in which said piston is mechanicallyconnected at its incoming side to a terminal end of said metallic armorsheath.

4. Terminal apparatus according to claim 1 wherein said tubular pistonis axially flared outwardly at opposite ends to form oppositely directedmouths with a narrow throat therebetween, said insulating cable jackettraverses the piston mouth facing the incoming end of said shell andpasses through said throat, and resilient sealing means is positionedwithin the piston mouth at said incoming end, whereby pressurized fluidin said conduit acts to compress said sealing means within said pistonmouth at the incoming end and against said cable jacket.

5. Terminal apparatus according to claim 4 wherein said tubular pistoncomprises a head portion including said oppositely directed mouths andan annular base ring bolted to said head portion and engaging saidsealing means in axial compression.

6. Terminal apparatus according to claim 1 wherein said tubular pistonis axially flared outwardly at opposite ends to form oppositely directedmouths with a narrow throat therebetween, said insulating cable jackettraverses said throat and terminates in the piston mouth facing theoutgoing end of said shell, and said body of resilient insulatingmaterial fills said piston mouth facing the outgoing end and iscompressed by said mouth facing the outgoing end radially against saidcable jacket and said insulated conductor.

7. Terminal apparatus according to claim 6 wherein said aperturedclosure cap is formed to provide a flared mouth facing the piston mouthat the outgoing end of said shell, a plug of rigid insulating materiallies within said flared mouth of said closure cap, said plug beingaxially apertured to permit passage of said insulated conductor, andsaid body of resilient insulating mate'- rial is compressed between saidinsulating plug and the opposing mouth of said piston.

8. Terminal apparatus according to claim 7 wherein said plug of rigidinsulating material provides a flared mouth surrounding said insulatedconductor and facing the piston mouth at'the outgoing end of said shell,said body of resilient insulating material being compressed within andbetween the opposing mouths of said piston and said insulating plug.

1. Terminal apparatus for a pressurized fluid conduit and an enclosedelectric cable having a fluid impervious insulating jacket whichcomprises, a tubular shell enclosing said cable and having an incomingend coupled to said conduit, an apertured closure cap in the oppositeoutgoing end of said shell, said cable jacket being terminated withinsaid shell and said cable including an insulated conductor passing outof said shell through said closure cap, a tubular piston slidablymounted in said shell and embracing the terminal end of said cablejacket in sealed relation, and a body of resilient insulating materialfilling said shell between said piston and said closure cap andsurrounding said insulated conductor whereby fluid pressure on theincoming side of said piston increases sealing pressure of saidresilient body against said insulated conductor.
 2. Terminal apparatusaccording to claim 1 which includes also a sealing ring interposedbetween said piston and said shell.
 3. Terminal apparatus according toclaim 1 for an electric cable having an external metallic armor sheathin which said piston is mechanically connected at its incoming side to aterminal end of said metallic armor sheath.
 4. Terminal apparatusaccording to claim 1 wherein said tubular piston is axially flaredoutwardly at opposite ends to form oppositely directed mouths with anarrow throat therebetween, said insulating cable jacket traverses thepiston mouth facing the incoming end of said shell and passes throughsaid throat, and resilient sealing means is positioned within the pistonmouth at said incoming end, whereby pressurized fluid in said conduitacts to compress said sealing means within said piston mouth at theincoming end and against said cable jacket.
 5. Terminal apparatusaccording to claim 4 wherein said tubular piston comprises a headportion including said oppositely directed mouths and an annular basering bolted to said head portion and engaging said sealing means inaxial compression.
 6. Terminal apparatus according to claim 1 whereinsaid tubular piston is axially flared outwardly at opposite ends to formoppositely directed mouths with a narrow throat therebetween, saidinsulating cable jacket traverses said throat and terminates in thepiston mouth facing the outgoing end of said shell, and said body ofresilient insulating material fills said piston mouth facing theoutgoing end and is compressed by said mouth facing the outgoing endradially against said cable jacket and said insulated conductor. 7.Terminal apparatus according to claim 6 wherein said apertured closurecap is formed to provide a flared mouth facing the piston mouth at theoutgoing end of said shell, a plug of rigid insulating material lieswithin said flared mouth oF said closure cap, said plug being axiallyapertured to permit passage of said insulated conductor, and said bodyof resilient insulating material is compressed between said insulatingplug and the opposing mouth of said piston.
 8. Terminal apparatusaccording to claim 7 wherein said plug of rigid insulating materialprovides a flared mouth surrounding said insulated conductor and facingthe piston mouth at the outgoing end of said shell, said body ofresilient insulating material being compressed within and between theopposing mouths of said piston and said insulating plug.